1. Field of the Invention
The present invention pertains to systems for controlling and stabilizing the moisture content of soil around and beneath the foundation of a building. More specifically, the present invention pertains to an improved soil moisture stabilization system by which water flows to or is prevented from flowing to soil around and beneath the foundation of a building, depending upon measured moisture content thereof.
2. Description of the Prior Art
Soils expand and contract to a degree relating to the moisture content therein. Certain types of soil, such as the clay soils of the Gulf Coast, are highly expansive. For example, one dry cubic foot of Beaumont/Lake Charles clay soil can expand up to four cubic feet with the addition of moisture thereto. One can readily see that buildings may be damaged by such expansion and contraction of the soils surrounding and beneath the foundation. Repeated wetting and drying of the soil, particularly when done unevenly, can place great stress on foundations resulting in tilting, cracking and destruction of the foundation. This, of course, often results in damage to structures supported on such foundations.
Several years ago, systems began to be developed for stabilizing the moisture content of soil around and beneath the foundations of buildings. These early systems were nothing more than simple soaker hose, drip irrigation systems controlled by an individual on an as-needed/as-remembered basis. Small soaker hose was laid on the ground, across sidewalks and up to driveways, patios, pool aprons, and other obstructions which covered part of the support soil around and under a building. Although such systems may have helped in some cases, they were very inefficient due to lack of uniform distribution of water and the lack of access to soil under driveways, sidewalks and the building foundation itself. The, soaker hoses utilized with such systems do not evenly distribute moisture without proper flow and pressure controls. Neither are they capable of distributing the volume of water necessary to correct the supporting soils' loss of moisture. These hoses are manufactured to operate at very low operating pressures and at low flow rates, typically one quarter gallon per minute. The low operating pressures allow relatively large flow of water near the point of entry but with volume severely diminished in a short distance. The hose frequently clogs up due to low operating pressure. Intrusion of insects, such as ants, typically create problems with such systems.
As previously mentioned, the conventional soaker hose/drip system was not buried or placed under concrete. This eliminated water flow to many areas since most buildings have some form of concrete attached to the foundation, e.g., driveways, sidewalks, patios, porches, etc. To attain and maintain uniform support around a foundation a properly designed/engineered moisture delivery system should be able to distribute water under such concrete areas. In fact, such a system should have the capability of delivering water to the soil underneath the foundation supported thereon. More recently, simple irrigation timers and/or controllers have been added to foundation watering systems. Although this does improve the distribution of water, such systems also have limitations. The controller can only control the number of times or length of time that a zone or irrigation section will be watered. It will not determine the moisture content of the soil being watered. Although such controllers can be pre-programmed for watering cycles of pre-determined length or duration and times between cycles, they often result in overwatering of the supporting soil and cannot compensate for variable moisture content in separate zones or areas of the soil around and beneath the foundation of a building. If the soil is overwatered, it can cause severe problems. The soil may actually be liquified, totally destroying its supporting ability. Overwatering can also cause subterranean erosion in which support soil is actually washed away.
Thus, prior art systems for stabilizing moisture content of soil around and beneath the foundation of a building leave much to be desired. Although they may operate with limited success, the prior art systems are not uniformly effective and efficient. Substantial improvements thereto are needed.